1. Technical Field
The present disclosure relates to full duplex communications and more specifically to providing compatibility of full duplex communication devices and systems with existing half duplex devices and systems.
2. Introduction
Current wireless communications systems cannot transmit and receive on the same frequency at the same time, i.e., these networks do not operate in a full-duplex fashion. As a result, such networks are either time-division duplex (e.g., WiFi) or frequency-division duplex (e.g., cellular). A challenge in achieving full-duplex communication is a large power differential between the “self-interference” created by a node's own radio transmission and the signal of interest. This large power differential exists because the self-interference signal has to travel much shorter distances compared to the signal of interest. The large power differential swamps the signal of interest due to finite resolution of analog-to-digital conversion.
Previous efforts to suppress self-interference have reported success for only very short range line-of-sight (LOS) channels like those encountered in personal area networks such as Bluetooth and Zigbee. Such small range abilities continue to remain a bottleneck for including full-duplex in practical wireless networks. By overcoming the limitations associated with previous systems, full-duplex communications can extend communication range while increasing bandwidth.
However, initial introduction of full-duplex communications requires coexistence with regular, half duplex communication systems. To take full advantage of full duplex communications while continuing to comply with existing half duplex communications, the Medium Access Control (MAC) protocol which regulates access to the shared medium requires modification. MAC protocols can help decide when a node accesses a shared medium, resolve potential conflicts between competing nodes, correct communication errors, and control the flow of network traffic.